diff --git a/configure.ac b/configure.ac
index 915125d..3475611 100644
--- a/configure.ac
+++ b/configure.ac
@@ -48,7 +48,7 @@ else
 	PKG_CHECK_MODULES([libxtables], [xtables >= 1.4.3])
 fi;
 AC_CHECK_HEADERS([linux/netfilter/x_tables.h], [],
-	[AC_MSG_ERROR([You need to have (/usr/include/)linux/netfilter/x_tables.h])])
+	[AC_MSG_ERROR([You need to have linux/netfilter/x_tables.h, either through /usr/include or the iptables directory (--with-xtables=)])])
 
 regular_CFLAGS="-D_LARGEFILE_SOURCE=1 -D_LARGE_FILES -D_FILE_OFFSET_BITS=64 \
 	-D_REENTRANT -Wall -Waggregate-return -Wmissing-declarations \